bone marrow

noun

: a soft highly vascular modified connective tissue that occupies the cavities of most bones and occurs in two forms:

a

: one that is yellowish, consists chiefly of fat cells, and is found especially in the cavities of long bones

b

: one that is reddish, is the chief site of blood cell formation, and occurs in the normal adult in cancellous tissue especially of certain flat bones

called also red marrow

Examples of bone marrow in a Sentence

Recent Examples on the Web

Traditional French bordelaise is a red wine and bone marrow reduction. — Susan Stapleton, Des Moines Register, 22 Sep. 2026

What a full-body scan can actually find A whole-body MRI or ultrasound can pick up benign and cancerous tumors, abnormalities in bone marrow or lymph nodes and irregularities in major blood vessels. — Hanna Wickes, Miami Herald, 21 Sep. 2026

Papa, 63, had been recovering from leukemia and complications after a bone marrow transplant in March. — Nicole Buss, Sacbee.com, 20 Sep. 2026

Adelynn was just 4 years old when she was diagnosed with B-cell acute lymphoblastic leukemia, a rapidly progressing blood cancer that begins in the bone marrow. — Toria Sheffield, PEOPLE, 19 Sep. 2026

Word History

First Known Use

1590, in the meaning defined above

Rhymes for bone marrow

• caballero
• mescalero
• aero
• faro
• garo
• narrow
• pharaoh
• sparrow
• taro
• bolero
• bracero
• estero

Kids Definition

bone marrow

noun

: a soft tissue rich in blood vessels that fills the cavities of most bones and occurs in two forms:

a

: one that is yellowish and fatty and is found especially in long bones (as the femur)

b

: one that is reddish, is the main place where blood cells are formed, and in adults is limited especially to certain flat or short bones (as the ribs)

Medical Definition

bone marrow

noun

: a soft highly vascular modified connective tissue that occupies the cavities and cancellous part of most bones and occurs in two forms:

a

: a whitish or yellowish bone marrow that consists chiefly of fat cells and is found especially in the cavities of the long bones

called also yellow marrow

b

: a reddish bone marrow that contains little fat, is the chief site of red blood cell and blood granulocyte formation, and occurs in the normal adult in cancellous tissue especially of certain flat bones

called also red marrow